Method of agglomerating ores.



P. O. HARDING.

METHOD OF AGGLOMEHATING ORES.

APPLICATION FILED IuIIE I2, I9I5.

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` 'PHILIP O. HARDING, OF PITTSBURGH, PENNSYLVANIA.

METHOD OT AGGLOMERATNG DRES.

i scenes.

i To all 'whom it may concern:

glieny and State of Pennsylvania, a citizen of the United States, nave invented or discovered certain new and useful Improvements in Methods Agglomerating O res, of which improvements the following is a specification.

My invention relates to the agglomeratmg of ore, particularly of iron ore, a procedure commonly called sintering.

In the ordinary operation of blast fur1 naces, particularly when finely pulverized ore is used, there is a large production of flue dust.4 This flue dust, though rich in iron, is, because of its finely divided condition, diiicult to handle, and the recovery of 'its iron content has been found to be so costly that great quantities of flue dust from blast furnaces have been regarded as waste. Of late years efforts have been iliade to bring the flue dust to a condition better adapted for re-introduction into the blast furnace as part of the furnace charge, by submitting it iirst to the sintering operation. The flue dust is mixed with finely divided ore and the mixture is ignited. The flue dust is'rich in carbon anch' with provision for a suitable supply of air to sustain combustion, the mixturey is changed by burning from a. loose friable material to an aggloinerated, clinker-like mass. The precise chemical changes'which occur are obscure and but imperfectly understood. Necessarily, they vary as thev chemical composition of the mass under' treatment varies. But the physical' change, indicated above, is the one which is important to the furnace operator. y

It has been found a matter of great difliculty to obtain a uniform agglomeration and produce an'article which does not contain within its body pockets of unaltered and friable material. Furthcrn'iore, apparatus heretofore devised such as is productive of material nearest to the furnaceinans requirements, is exceedingly costly both to in stall and to maintain in repair. My invention consists primarily in subjecting a body of material to be agglomerated (which ordinarily will be a` mixture of Specification of Letters Patent.

Mit-enten Jan. et, 19H5.

Application filed June 12, 1915. Serial No. 33,767.

flue dust and nely divided iron ore) to a progressive combustion which advances through the body, in causing the current of combustion-sustaining gas (which ordi nai-ily will be atmospheric air) to flow to the region of combustion through that portion of the body which has already been subjected to the agglomerating lire, and at the same time effecting a breaking-up or fragmentation of that portion of the body through which the flow Aof combustionasustaining gas is advancing. Such breaking up of the mass opens toe pockets of unchanged friable material, and the current of air sweeps the `material so exposed back into the region of combustion where, nowy mingled with air and brought to proper temperatur-mit will undergo ignition and agglomeration.

My invention further consists in apparatus for performing the operation herein above deiined. This apparatus is illustrated in the. accompanying drawings, and l shall explain my invention by reference thereto.

In this application do not lay claim to the apparatus employed but only to the method. In a co-pendine, application filed July 3rd` 1915, Serial No. 37922, ll make claim to the apparatus.

Figure l shows the apparatus in preferred form and in vertical medial section; Fig. 2 is a view on larger scale and in vertical medial section of the spreader and pusher deta'ched, which in Fig. l is shown in operative position; Fig. 3 is an end view of the said spreader and pusher; F ig. l is a View corresponding to Fig. l showing the apparatus in modified form; Fig. 5 shows in longitudinal section the passageway oi' hot tube of the apparatus of Fig. 4; Fig. 6 is a View in end elevation and Fig. 7 a View in transverse section of the tube of Fig. 5, the plane of section of Fig. 'i' being indicated by the line Vil-Vil, Fig. 5; Fig. 8 shows in side and in end elevation an extractor applicable to the apparatus shown in F ig. -l and Fig. 9 shows in longitudinal section and in end elevation an extractor of another form.

i Aeferring iirst to Fig. l, l indicates a chamber within which is contained a body ot' material under treatment. lVithin this chamber the ignition occurs which eects agglomeration, and this ignition takes place progressively through the body of material. Such a procedure is conveniently accomplished by making the chamber of the tubular form shown, maintaining a zone of combustion at an intermediate point in the length of the tube (near the intake end) and in causing the material under treatmentto advance by continuous feed through the tube. The zone of combustion is conveniently defined and combustion maintained by a heat-giving apparatus surrounding the tube. As shown in the drawings, this apparatus takesthe form of an annular reverberatory chamber 2. The particular nature and character of this heat-imparting apparatus are not ofthe essence of the invention in its broader aspect, land indeed a4 proper selection and mixture of material to be treated and a proper control of the supply of vcombustionsustaining gas may render the employment of any such heat-imparting apparatusyunnecessary.

, In` Fig. 1 A indicatesthat portion of the body of material under treatment which has just been introduced into tube 1, B indicates apparatus shown in'Fig. l are these: The

tube 1 is arranged vertically; it iares downwardly; and the charge within the tube rests upon a support This support is conveniently of circular plan, arranged con ccntrically beneath the vertically arranged `downwardly fiaring tube, and it is spaced at an interval from the lower edge of the tube.v Through this space the finished material finds escape. The support 3 is conveniently conical, as shown, and it is rotary on a central axis. The-effect of rotation of the supper-t3 is that the'downward sinking body of material is discharged through the annular orifice between the s'upport and thelowei" `edge of, ipe 2, `and the further f e whole agglomerated portionof the charge, marked C, to strains wliicli'eause it `to break up, to separate into 'fragments-fAnd the consequence is that the indrawn streams of air flow freely through thev crevices so opened,` and where the .indrawn air encounters friable and un- `a,fglomerated material it will blow such may terial back into the zone of `combustion where it will undergo the combustionwhich it had fortuitously escaped. Suction, 1s

geous because the velocity of the current of air flowing from tube l is thus rapidly `checked and accordingly the arrested current of air deposits practically all of whatever burden of powdery material it may have carried from tube 1. A water spray 6 may be provided to play upon the upper surface of the charge within tube l, and its purpose is tothe same end, to keep down and carry back into the tube whatever dust tends to rise from tl1e n1a terial under treatment. As `is well known itis common to mix the material with water in preparation for treatment, and for this same purposeto prevent the iiyingof dust.` The supply of water through this spraying apparatus may manifestly be controlled as desired. The chamber 5 thus is seen to be a closed chamber. The drawings show a feed pipe 7 leading toit anda worm feed within the pipe. 1t will be understood that such a feeding mechanism may be employed to feed in the material, continuously or intermittently as desired, and without serious interference with the maintenance of a draft through tube 1 by the means which have been described.

A spreader and pusher is indicated at 8 and more lfully illustrated in Figs. Q and lt consists essentially of a sweep like arm or arms 9 carried on a shaft 10 which is mounted centrally above tube l. Shaft 10 is rotatable and as it turns the arm 9 (which is arranged within tube l and at its upper end at the level of the normal surface of the body of infed material) sweeps and levclsthe material which is gradually being fed in through conduit 7. It will be observed, in this connection, that'the hopperlike bottom of chamber 5 serves not merely to check the rise of dustl (as explained) but to collect and deliver to tube 1 whatever dust settles from the inflowing stream of air and whatever portion of the material fed in from conduit 7 falls to one side. Thus the spreader S maintainsan even distribution of the charge in tube 1. be carried on shaft 10, 'rotating with it but preferably free to slide upon it as the shaft moves,longitudinally. uThis sweep traverses the sloping hopper surfaces and 1assists in carrying into tube 'whatever material lodges on vtheseI sloping surfaces. At times in the course of the operation the tabel may become clogged by material skulling and.

A sweep 20 mayl muy advantageously i of @kwin al Calling Within it. The ineinliw 8 s ii the zone o: combustion. To luit end the shaft l0 is mounted net only for ioziion but also for longitudinal reeipiocation. The structure is conveniently enii'iecl on ai p1' perl57 Weighted lever o1' 4 milking beam l l1 und :i suitablel hmnlle l2 may be pio Yclecl for driving the member 8 up and down to effect ille einils described.

f ltieinzilns oul;- lio oeill ulenion lo eel'- tfiin fuitliezz features ol' the apparatus ulil'fn be employed. 'i'lie support 3 for llie material wiliin lube l. and the worm 5" f l wi'dxiu eonouit 7 may both be pou'er--cli'ii'eig und heoe two parts may, fas Shown, be (li'l'veii in coordination, so that 'feed unil 'ellsel finge slnill be ef- :i Constantly i'minteinel i The lowerportion of tube il und l. lo suppoiii 3 muy :19 indicated ne perforv 'to afford material wi'sliin tube "i,

The tube. l und the piolimae poi-tions of Chamber 5, where liii'li teinpeiaues maintained, muy be :oi'nel of fire lnlolc built in un iron iii-eme Woik. lie Stem an@ heelal, of the splende? and pusllei' neg as: shown proviclecl with internal passages for ille circulation e The A:,imus ol' um be unele lood with n fen' Ulm (n. The tube lig lng' ing i'erion. ni'iengfil, .i position; lle eonclut Y for Y l u motori: l nils into lie n'iou'li o'i'' w. und the Y -fezf nfl pusher me iilipoeil with. 'lie intake no in lyola is pio-vloed? :in ynn'euluily shown i i l' und iwitli lugy 1,25, ugziinrs't which lle fonclui TU' bearing and leu'een which lle current un; is drawn, Hnimigli an annule? elizlmliex' fr wlzei Sui u the C@ l This elminlieif :n z; si; in n." pz gmfexii ful lli; pm'ioul l'ln, mieke eu-i having' mulini ils well. lli y; become pun-lied @E inzileiiml; nl

of or other combustion-nourisliing gas, oombusion n'iliin die body in the tube may loe 'feeilitneel or niensiiled, and the oxue nel liezitei 2a muy oi' muy not be en'iployed. tucli a Supply of combustible gas may meni- 'estly 'ne provided in connection with the apparatus of Figs. l.

The Worin feed wiliin conduit Y is water eoolefl as :show i.

A Shafi- :icli': need amil ie zioteel longitudinally, is inounteel'opposite the. disclnii'ge enel of tube pon it may be mounted, eiliei the eX- tmcoi' of Fig. 55, siii" ils blades forming un iineii'upeel helix, oi' lie, oi'own-like drill of Fig. 9. These are che iii-inns in this case employed to breuk up und form fissures in body o` :il it advances 'ii-oni the,

and ngglome 'a;ion, und l motion of the glomeiulecl nmufizi from lube la. Such m lies already been explained,

` lie strewn of nii' go Elie interes elle an to blow back into Combi lli Cf ileseiijpion I have spounflei rezimen in.

o snicl that liis will ieniains only to be limiailon upon my o il; is; not yassent o be lzeateel. For al to mu; flue dust non order obtain mateiial I,flomeizued; eolie brame i wif?. lice-ri oio ane.

" my proeoelure; an iron fe sulfur content neefls any Carbon.Containing isell" oo ziggloinei'aefl. Snlliee o indiene that wl i :we rliileu eniou:

oi e

u gglomoiation llerem subjeen:

oo li.,

oli comb-u tion oei-zito@ und. 'a'ugn'ieueil irl oi" oro zggloinei'niion here- 11 eonsigils in slime-sting el ll", .rotatable and Capable o1'2 being 75 e of fluo iiusi'; once :er oi the particular 100 lie minimo l0 body of material to a' progressive combustion, breaking into fragments'the agglomerated portion of such body left behind as combustion advances, and causing a stream of combustible gas to ilow to the point of combustion through such agglomerated and fragmented portion of the body. 3. The method of ore agglomeration herein described which consists in causing the body of material under treatment to advance by continuous feed through a Zone of high temperature, breaking into fragments the agglomerated portion of said body advancing from such zone, and causing a current of combustion-sustaining gas lto flow to such zone of high temperature through the portion of the body of material agglomerated and fragmented as above indicated.

l. The method of ore-agglonieration herein described which consists in causing the body of material under by continuous feed through a zone of coinbustion, subjecting such body of material to treatment to advance a spray of water in the rear and to a current of air owing through it from front to rear and in breaking and spreading the fragmented mass of material as it advances beyondsaid zone of combustion.

The method of ore-aggloineration herein described which consists in causing the body of material under treatment to descend through a vertically arranged and downwardly flaring passageway' and in such progress to pass through a zone of combustion, causing an ascending stream of air to penetrate said descending body of material,

and causing such descending mass of 1natei rial to be broken up and subjected to a more .searching penetration ofthe said ascending stream of air as it descends beyond said zone of combustion.

Intestiniony whereof I have hereunto set my hand.

y PHILIP O. HRDING.

lWitness f FRANCIS J. TOMASSON. 

